Unseen World!

US military researchers are developing a method for communication that uses lasers to make sound underwater.

The approach focuses laser light to produce bubbles of steam that pop and create tiny, 220-decibel explosions.

Controlling the rate of these explosions could provide a means of communication or even acoustic imaging.

Researchers at the US Naval Research Laboratory say the approach could be used for air-to-submarine or fully underwater communication.

One of the peculiar effects of high-intensity laser beams is that they can actually focus themselves when passing through some materials, like water.

As the laser focuses, it rips electrons off water molecules, which then become superheated and create a powerful "pop".

Because different colours of light travel at markedly different speeds underwater, the precise location where different colours focus together could be manipulated by the suitable design of a many-coloured input pulse.

The approach could use commercially available lasers

Those same focusing effects are significantly reduced in air, so that a laser "signal" could be launched from an airborne source to communicate with submarines, so that they do not need to surface.

The idea could also be used for underwater acoustic imaging, by using a moveable mirror to direct the pulses into an array of pops whose echoes can give a detailed picture of underwater terrain.

The total proposed American defense budget for 2008 is more than half a trillion dollars—with $75 billion of that set aside for research and development. For decades, the Pentagon’s investment in science and technology has produced widely hailed achievements like the Internet and the Global Positioning System. It has also backed quixotic and costly failures, like space-based lasers. And sometimes it has gone off the deep end, funding such things as psychic spies and weapons that defy the laws of physics.

The Department of Defense began systematically funding basic and applied research in a big way after World War II. Today the Pentagon’s investment in science R&D remains a cornerstone of the country’s national security strategy. Yet in the aftermath of the low-tech attacks

Unmanned Aerial Vehicles (UAVs), like this MQ-9 Reaper, are receiving a great deal of funding.
Image courtesy of USAF/SR. Airman Larry E. Reid Jr.

of 9/11, the growing insurgency in Iraq, and the threat of worldwide terrorism, technology experts both within and outside the Pentagon are questioning whether Defense Department research is producing the results that America needs.

So what are we getting for our money? That $75 billion budget covers a vast array of projects, from perfecting new weapon systems like the Joint Strike Fighter plane to studying pure physics. Focusing on the research side of R&D, DISCOVER looked at four key areas where the military is placing its bets: hypersonic vehicles, laser technology, using information technology and neuroscience to combine human and machine on the battlefield, and employing sociology and psychobiology to combat terrorism.

There are a lot of myths and misconceptions surrounding the current M16A1, M16A2, M4, M16A4NATO 5.56 round and its effectiveness on the battlefield. Now before you make a judgment as a soldier or as a firearm enthusiast (a more euphemistic way of saying “gun nut”), consider your sources. Who is it that is telling you the 5.56mm, or .223 if you prefer, is an ineffective round? Is this source an armchair general who has watched Blackhawk Down one too many times; or a Navy Corpsman who has been attached to a MEF fighting in Fallujah and has seen, treated and inflicted these wounds with his own M-4? People look at the .30-06 round from their grandfather’s M1 Garand and the 7.62×51mm round from their dad’s M-14 and compare it to the M-16/M-4’s 5.56 and think; “Wow, this is considerably smaller. Therefore, it must be less effective.”

M16A1, M16A2, M4, M16A4

Now Joe Nichols had it right when he said, “Size Matters.” However, when you are talking about combat cartridges this is not always the case, and I say that hesitantly. When the 5.56 was derived from Remington’s .223 in the late 1950’s, it was meant as a “force multiplier” if you will. By that I mean a soldier could literally carry twice as much ammunition as one who has the older 7.62 for the same weight. They wanted a soldier who could stay longer in the field without re-supply and could literally out-last and out-shoot the enemy in many aspects. The 5.56 is an incredibly fast and flat shooting round compared to the 7.62, but is under half the bullet weight.

So one might ask; ‘How in the world can a smaller bullet be more lethal than a bigger one?” One word: cavitation. Cavitation is the rapid formation and collapse of a substance or material after an object enters it at a relatively high velocity. I guarantee you have seen cavitation before. Next time you are in the pool or on the boat, look at your hand as it passes through the water or the propeller spinning. In both cases you will notice bubbles on the trailing edge of each. You see this because the liquid water falls below its vapor pressure. Without getting into physics and the hydrodynamics behind it, I’ll just leave it at that. When a human body is hit with a 5.56mm 62-grain bullet traveling at 3,100 feet per second; essentially the same thing happens but much, much more violently. For a split second, the cavity created inside the human body by the round from an M-16/M-4 is about the size of a basketball (if hit dead center of mass). The 5.56 creates this massive cavitation by tumbling through the body initiated by inherently unstable flight.

5.56 ballistic test

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MONTREAL — Canadian soldiers are bringing home from dusty Afghanistan a powerful, drug-resistant superbug that health officials have been worrying about for several years.

Three Canadian soldiers who recently returned from Kandahar carrying so-called "Iraqibacter" are under quarantine at a civilian hospital in Quebec City.

Two civilian patients who came in close contact with the soldiers at Hopital de l’Enfant-Jesus have also been isolated for fear they may have contracted the superbug officially named Acinetobacter baumannii.

The hospital-acquired germ, commonly found in soil and water, strikes weakened immune systems, especially in those recovering from wounds.

It has been known to cause conditions such as pneumonia, meningitis as well as blood, urinary tract and wound infections.

Some people carry the bacteria on their skin without showing symptoms.

Two years ago, the Public Health Agency of Canada warned Canadian hospitals that outbreaks could happen after wounded soldiers returned home from Afghanistan either sickened by the strain, or simply carrying it in their system.

The department did not immediately answer requests for an interview on the subject Thursday.

A 2007 report in the publication Wound Care Canada said incidences of the strain have increased in U.S. military hospitals.

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